Electrolytic deposition of metals



M. M. MERRITT ELEGTROLYTIG DEPOSITION 0F METALS sept. 2s 192e.v 1,601,690

Filed August 20' 1925 3 Sheets-Sheet 1 (h (Sm 1,601,690 M. M. MERRITT ELECTROLYTIC DEPOSITION OF METALS Sept. 28 1926.

Filed August 20, 1925 3 sheets-sheet 2 Sept. 28 1926.

M. M. MERRITT 4 ELECTROLYTIC DEPOSITION OF METALS Filed August 20. 1925 Z Sheets-Sheet s lllllllllIllllllllldlllm Patented sept. 28,1926.

"UNITED sTATEs ia'rsN'iI OFFICE..

AIMiA'lTIEIIEW M. MERRITT, 0F MIDDLETON, MASSACHUSETTS, ASSIGNOR TO INDUSTRIAL ,i DEVELOPMENT CORPORATION, F PORTLAND, MAINE, A CORPORATION 0F ELECTROLYTIC DEPOSITION OF METALS.

Appiication mea August 2o, 1925. swarm. 51,377.

My invention `pertains to improvements in electrolytic methods and apparatus, and. particularly to methods anduapparatus for making sheet metal by electro-deposition.

My invention will be best'understood from the .following description when readin the light ofthe accompanying drawings of one specific embodimentV of my invention selected for illustrative purposes, while the scope ofmy invention will be more particularly pointed out in the appended claims. In the drawings Fig. 1 shows a plan of apparatus arranged according to my invention;

Fig. 2 is a section on the line 2-2 of Fig. l;

Figs. 3 and 4; respectively are sections on the lines 3-3 and 4--4 of Fig. 2;

Fig. 5 is a fragmentary section on the line 5--5 of Fig. 1; and f n 4 Fig. 6 more or less diagrammatically illusvided with a conductive surface serving as a cathode upon which the sheet material to be formed is deposited. Preferably as illustrated by Figs. 3' and 5 the cathode consists of'an endless sheet of copper 6 surrounding the drum and having its surface treated with mercury to form a coating of amalgam 7 for the purpose of preventing adherence of the deposited sheet to the cathode during the stripping operation hereinafter described.

Preferably the copper sheet 6 is supported on a lead sheet 8, both sheets being received f in an annular recess in the drinn.' For t-he purpose of aiding stripping ofthe deposited sheet from the cathode and forgiving the or other suitable non-conductive material carried by the drum.

For placing the cathode in electrical communication with the source of electromotive force indicated at '10 in Fig. 2 I have shown a brush ll'cooperating with a ring 12- on the shaft 3, the latter being connected to the A sheet 8 (Fig. 5) by means of a conductor 13.

For stripping from the cathodes the sheets being continuously deposited thereon as the cathodes slowly rotate I provide rotating drums 15 to which the ends of the deposited sheets are secured, rotation of the drums 15 acting to strip the deposited sheets from the cathodes and to wind the sheets on the drums. a e

For rotating the drums 1 and 15 l'. have indicated a shaft 19 which carries lworms 21 (Fig. 2) meshing with worm gears 23 on the ends of the shafts 3 carrying the drinn 1, the shafts 3 carrying pulleys 25 belted by means of belts 27 to pulleys 29. The pulleys 29 drive shafts 31 which are connected by means of a friction-drive device 33 of-ilwell-'I known construction to shafts 35 which carry the drums 15. Thespeed 'of rotation ofthe pulleys 29 relatively to the speed of rotation' of the pulleys 25 is such that the friction drive device 33 tends to rotate the drums 15 at a peripheral speed somewhat greater than the peripheral speed of the drums 1, in consequence of which the'sheets 17 are maintained under tension, which facilitates the stripping operation and 'winds the sheets 85 tightly on the drums 15.

As indicated b Figs. 1, 2 and 3 the drums flrotirtiin troug s 37 preferably lined with sheet lead 39 or otherA suitable conductive material, the sheet lead constituting an anode 90 to the troughs 37 down aprons 43, and through the troughs lengthwise of the rotating cathodes in a swift-flowing continuous stream.

For regulating the amounts of electrolyte fed to the troughs 37 of each unit I provide suitable" gates 45.A The amount 4of electrolyte entering each trough 37 conveniently is suiicient to cause the electrolyte to contact with each rotating cathode to a depth of approximately one-thirdof its diameter, the level of the electrolyte being indicated.. by the dotted line 47 in Fig. 2.

To insure maintaining the level of the electrolyte substantially horizontal or parallel to the axis of the drum 1 so as to cause the sheet to be of uniform thickness I preferably provide each trough at the discharge side of the drum with a weir or dam best illustrated in Fi s.2 and 4. As shown the dam comprises a xed plate 119` which extends across the trough and va second plate 51 similarly positioned but supported by screws 537,and nuts 55 and slidingat its ends in vertical grooves'57 sothat 1t-.can be raised and lowered. The major portion of electrolyte'disch'arges, as 1s indicated by the dotted lines 59 in Fig. 2, beneath the mov able plate 51 of the dam, while a small portion of the electrolyte flows over the plate 49, the upper edge of the plate 49 for this purpose being preferably notched as is indicated at' 61. The frusto-conical portions 5 of the drum heretofore referred to promote a uniform and uninterrupted How of the l electrolyte.

The electrolytel discharging from the troughs 37 falls into a trough 63, and leav-V ing this trough by a pipel 65, is pumped by a pump 67 through a pipe 69 so as to elevate itv and Vdischarge it into a ,replenishing conduit herein shown as a tower 71. The tower contains suitable material 7 3 for replenishing the electrolyte, as for example ore, suitable salts, or scrap metal preferably the latter. The electrolyte after passing down- .wardly through the material 73 leaves the lower portion of the tower 71 through suit- 'i able orifices 75 and fiows by gravity down a trough 77 in communication with the trough 41 itbeing observed that by the means just described the electrolyte is continuously circulated past the cathode and over the surface y so of the electrolyte replenishing materia-l 73,

The negative terminal of the battery 10 or `other source of direct current electro-motiveforce is connected to the cathode as hereinbefore explained, while the positive terminal is connected to the insoluble conductive lining 39'ofthe trough4 37 constituting an anode by a Contact which runs the entire lengthA of the lining. The metal-bearing material 78`in the tower 71 is maintained at substantially the same potential as that of lining 39 by reason of the fact that the circulating electrolyte being a conductor places the ma;A terial 7 3 in electrical communication with conductive lining 39. Preferably acommon source of elect-ro-motive-force is employed for all of the units comprising a cathode 6 and insoluble conductive trough 39, the cathodes and troughs being connected in parallel to the respective terminals'of said source. Provided a suiicient potential is v impressed on the metal-bearing electrolyte replenishing material 7 3, the -metal of said material will dissolve in the electrolyte as voltage, must be suited to the particular metal or metals to be deposited. When my method and apparatus are used for depositing sheet copper on the cathodes the electrolyte employed is preferably a copper sulphate solution containing a low percentage of free sulphuric acid, and the material in the tower for replenishing the metal content of the electrolyte is preferably scrap sheet copper. For copper I have found that in order toI obtain best results with an insoluble anode the impressed voltage should notbe' less than one and one-half volts although with a soluble anode it is possibleto employ very much lower voltages. It will be understood that metallic cop-per is insoluble in dilute sulphuric acid at ordinary temperatures, although at hioher temperatures it is soluble in concentrated acid with the formation of objectionable sulphur dioxide. I have found that by impressing-a suitable voltage on the scrap copper in the tower 71 in contact with the electrolyte stream that I am able to effect f dissolving of the copper at ordinary temperatures without formation of sulphur dioxide.

My explanation of the above phenomena discovered by me is that the impressed voltage on the copper has an effect-analogous to that of raising the chemical valence vof the copper by oxidiza-tion vfrom zero to plus one or plus two at which value the cop-per will combine with the sulphate radical of the sulphuric acid of the electrolyte. For the presentexplanation the chemical valence of a metal in contact with an acid solution may be considered as the force, measured by the electrical charge of the vions of the metal which tends to cause the metal to enter into solution. This force I call for convenience the solution pressure of the metal, which ready in solution tending to prevent additional metal entering the solution.. This counter force I call for convenience the osmotic pressure of the metal in solution,

and I have found that by impressing on the metal in `contact with the electrolyte a voltage suiiicient to give the metal a solution pressure in excess of the osmotic pressure ofthe metal in solution, that I can replenish the metal content of the electrolyte to replace that deposited'on the cathode. For a given amount of metal surface eX- posed to the action of the electrolyte apparently the rate of replenishment is directly proportional to the rate of electrolyte flow and preferably I vary the rate of replenishment while keeping the impressed lvoltage constant by varying the ratio of the amountI of electrolyte to the amount ot' metal surface acted upon by the electrolyte, employing for this 'purpose means which will now be described. i y

For thus regulating the amount of metal 'dissolved by the electrolyte in the tower I have hereinshown means for ley-passing a ortion of the electrolyte around the tower.=

or this purpose I have shown a pipe 79 in communication with the pipe 69 and discharging into a `funnel 81 at substantially the same elevation as the discharge end of the pipe 69. The -funnel 81 is in communication with a pipe 83 which discharges into the trough 7 7 adjacent the intake end of kthe trough. baffles 85 being placed in the trough 77 so as to thoroughly mix the stream of electrolyte discharging from the pipe 83 with that discharging through the open-v ings 75.

I have found that best results can be obtained by preventingJ the metal content of the electrolyte from exceeding a maximum limit and from falling below av minimum limit. 'Preferably ,the amount of metal-l bearing` material in the tower and rate of electrolyte iiow are such as to cause the electrolyte when all of it passes through the tower to dissolve metal faster than the metal` creasing and dim-inshing the metal content .5.

of the electrolyte being `continued throughout the run.

For regulatingr the amount of electrolyte diverted from the pipe 69 to the pipe 79 Iorby-pa'ssing electrolyte around the metalbearing material in .the tower 71, I have indicated a butterfly-valve 86 at the point .of communication of these two pipes. As will be obvious movement of the valve 86 from its position lshown in Fig. l in' a countercloelnvisel direct-ion will divert .more electrolyte to the pipe 79, 4which pipe or better' regulating the flow therethrriugh is provided with a manually controlled valve 87 at its discharge end. v

If desired the butterfly valve 85'imay be operated manually, but as herein shown l have indicated it as operated by means of an electric motor 89, the shaft-of which car ries a worm 91 meshing with a worm gear 93 on the valve stem 94 of the valve .so that when the motor is rotated the vvalve will be slowly turned.

It desired the motor 89 can be controlled automatically in responset-o changes inthe specili: gravity ofthe electrolyte, the spe- 4 cific gravity as will be understood being a direct function of the metal content of the electrolyte. For controlling the motor `89 in response to changes lin specific gravity of the eletrolyte I have' shown at the discharge end of the' trough 77 a-:iioat or hydrometer 95, with which float is associated mechanism for effectingl rotation of the motor'to turn the valve'86 for diverting more electrolyte. through the pipe 79 when the speciticgravity increases to a desired value, and to etfect rotation of the motor 89 in an opposite direction to'turn the valve 86 for diverting less electrolyte,through the 'pipe 79 when the specific gravity decreases to a desired value.

Referring t-o Fig. 6 I have shoivr'i'the float 95 proridcd with a stem,97 for raising' and lowering a block ot insulating material 99 carrying a contact ring 101 for placing the spring contacts 103 and 105 respectively in electrical.communication with one ter.

minal of the battery 107 when the float falls and rises, the block of insulating ma-Vw terial 99 being preferably adjustably secured to the stem 97 by means of a rod 109 screw threaded into vthe. end of the stem 97- so that by turning the rod 109 the distanre between the Afloat and the contact ring 10i can be varied. The terminal of the battery opposite that connected to the ring 101 is connected to one end of eachof a pair of solenoids 111 and 11S` the other ends oi' these solenoids being connected to switch arms -115 and .1.17 which cooperate with contacts 119 connected to therespective spring contacts-103 and 105. On the end of'thc Vvalve stem 91 opposite the worm gear 93 is a disk 121 vof insulating material indicated in Figs. 1, 2 and 6. This disk as shown in Fig.-.l 6 carries a pair of adjustable stops 123 which cooperate with the switch arms 115 and 117 so that when the valve 86 has turned through an angle determined by the adjustment of thel stops one of the stops 123 will contact the associated switch arm and move it out of contact with its 'associated contact 119, while the other stopv -123 permits a spring 125 associated with each switch arm to move the other switch arm'into contact vwith its associated contact 119.

be energized, and this by means of switch mechanism hereinafter. described will cause the motor to rotate in such direction as to turn the disk 121 and butterfly-valve 86 as viewed'in Fig. 6 counter-clockwise so as I, to divert more electrolyte around the tower 71. lWhen the right hand stop, -123 comes into contact with the arm 115 the4 latter will b'e moved from in contact with its con- 'tact 119 which will interrupt the circuit through the solenoid 113 and cause the motor`-to cease rotating. The movement of the l disk'121 which took place while the motor was rotating will cause the left hand stop 123 to permit the switch arm 117 to move into contact with its associated contact 119 so that when the float falls due to a decrease in the speciic gravity of the electrolyte and establishes communication between the'contact ring 101 and the lower spring contact `103 the solenoid 111 will be energized to effect rotation "of the motor and moveA the valve 86 and disk 121 back to the position shown by Fig. 6.

Each of the solenoids 111 and 113 has associated therewith an armature 127 attached to a plate of insulating material 129 normally held in horizontal position by a pair of springs 131. The plate 129 carries on its under side a pair of contacts 131 which as indicated are connected to one side of a source of electromotive force and -a second pair of contacts 133 connected to the opposite side of the same source of electromotive force. Cooperating with 'the contacts 133 is a pair of contacts 135 and cooperating with the contacts 131 is a pair of contacts 137, these four contacts being insulated from each other by insulating strips'134. The opposite terminalsof the motor are respectively connected to one contact 'of each the airs of contacts 135 and 137 at opposite si es of the insulating strips 134; sol that when the solenoid 113'swings the plate 129 about its pivot 139 to move the right hand contacts 131 and 133 into 137 the motor will' be posite direction.

.the left hand contacts 131 and 133 into contact with the associated contacts 135 and rotated in the op As an example of the practice ofrmy invention but without limitation thereto l'.

have de osited on a single unit sheets of copper ve and one-half thousands of an inch in thickness on a cylindrical cathode 24 inches in diameter and 5 feet long, the surface of the cathode being spaced from the, surface of the trough lining approximately seven sixteenths of an inch and with an impressed voltage varying from 2.25 to 2.5 volts giving a current density of 250 Vamperes per square foot of cathode surface. ,Thel rate of rotation of the cathode was approximately one .revolution in 76 minutes and the rate of electrolyte flow from 75 tolOO gallons per minute. About 875 vpounds of sheet copper scrap threeeighths of an inch thick and cut in pieces two inches square was used for replenishing the metal contentof the electrolyte the crosssectional area ofv the mass of copper scrap transverse to the direction of the electrolyte flow being about two square feet, though in a plural installation as illustrated the amount of copper scra would normally be considerably increase In this example the copper content of the electrolyte was controlled to maintain it between lower and upper limits of approximately 26 and 32 ounces of copper sulphate crystals per gallon corresponding to maintaining the spe' cific gravity of the electrolyte between approximately 1.18 and 1.24 in the presence l of from 6 acid.

percent to 10 percent of sulphuric ,It will be understood that` the percent sulphuric acid content of the electrolyte varies as an inverse function of the copper content, so that in the above example of the practice of my method when the copper content was at 32 ounces of copper su phate crystals per gallon of electrolyte the acid concentration was at its lower limit of 6 percent and when the copper content was reduced to its lower limit of 26.ounces of copper sulphate crystals per gallon the sulphuric aci-d concentration was 'at its upper limit of 10 percent.

I have found that by passing the electrolyte in a rapidly flowing stream vthrough the space between the insoluble anode and rotating cathode where the latter is in close proximity to the former I am able to use a low impressed voltage with high current density causing an exceedingly rapid deposition of metal on the cathode without the y .cordino' to my invention andv one specific way o performing my method it is to understood that I am notlimited thereby to their particular details, but that within the scope of my invention wide deviations may be made -therefrom without departing from the spirit of my invention.

1. Electrolytic apparatus comprising, in combination, a cathode providing a moving cathode surface, and conduit means of insoluble conductive material constitutingan anode for guidingthe electrolyte in a swiftfiowing continuous stream in contact withsaid cathode surface.

2. Electrolytic apparatus comprising, in combination, a cathode providing a moving cathode surface, and conduit means of in'- soluble conductive material constituting an anode for'guiding the electrolyte ina swiftflowing continuous stream substantially transverse to the direction of movement of saidcathode surface and in contact therewith.

3. Electrolytic apparatus comprising, in combination, a cathode providing a moving cathode surface, and conduit means of inv'soluble conductive material constituting an anode for guiding the electrolyte past said cathode surface in contact therewith from one side thereof to the other in a swift-flowing continuous stream.

4. Electrolytic apparatus comprising, in combination, a cathode providing a moving cathode surface partially in contact with the electrolyte, and conduit means of insoluble conductive material constituting an anode for conducting the electrolyte ina swift-flowing continuous stream past the vportion of said cathode surface in contact with the electrolyte. 4

5. Electrolytic apparatus comprising, in combination, a cathode providing a moving cathode surface partially in contact with the electrolyte,V and conduit means of insoluble conductive material constituting an anode for conducting thel electrolyte in a `swift-flowing continuous stream substantia-ily transverse to the movement of said cathode Asurface past the portion of said Y cathode surface in contact with the electrolyte. v

G. Electrolytic apparatus comprising, in combination, a cathode providing a moving Vcathode surface partially in contactv with the' electrolyte, and conduit means of insoluble conductive material constituting an anode for conducting the electrolyte past 4the portion of said cathode surface in contact with the electrolyte from one side of `said cathode surface to the other in a swiftf l making l stripping from said cathode ,surface theA sheet material deposited thereon, and means for replenishing the electrolyte with metal content.

8. Electrolytic apparatus for making sheet material comprising, in combination, means providing a slowly moving endless cathode surface, means for fiowing the electrolyte transversely to the movement of said cathode surface in a swift continuous stream in contact with said cathode surface comprising conduit means of insoluble conductive material constituting an anode, means for stripping from said cathode surface the sheet material deposited thereon, and means for replenishing -the electrolyte with metal content.

9. Electrolytic apparatus for making sheet material comprising, in combination, means providing a slowly moving endless cathode surface, means for flowing the electrolyte from one -side of said cathode/surface to vthe other in a swift, continuous stream in contact with said cathode surface comprising conduit means of insoluble con 'ductive material constituting 4an anode,

vsheet material deposited thereon, and means for replenishing the electrolyte with metal content.

11. Electrolytic apparatus for making sheet material comprising, in combination, means providing a moving, endless cathode surface, meansv for lowing'the electrolyte in a swift, continuous stream in Contact with said. cathode surface comprising conduit means of insoluble 'conductive material constituting/ an anode, means for stripping from said cathode surface the'sheet material deposited thereon, and means for replenishing the electrolyte with metal content after said electrolyte flows from in contact with said cathode surface.

12. Electrolytic apparatus for making sheet material comprising, in combination, means providing a moving, endless cathode surface, means for flowing the electrolyte Substantially transverse to the movement of said cathode surface in a swift,'continuous stream in Contact with said cathode surface comprising conduit means of insoluble conductive material constituting an anode, means for stripping from said cathode surface the sheet material deposited thereon, and means for replenishing the electrolyte with metal content after said electrolyte ows from in contact with said cathode surface.

13. Electrolytic apparatus for making sheet material comprising, in combination, means providing a moving, endless cathode surface, means for flowing the electrolyte from one side of said cathode surface to the other in a swift, continuous stream in contact with said cathode surface comprising conduit means of insoluble conductive material constituting an anode, means for stripping from said cathode surface the sheet material deposited thereon, and means for replenishing theelectrolyte with metal content after said electrolyte flows from in contact with said cathode surface.

14. Electrolytic apparatus for. making sheet material comprising, in combination,

means providing a slowly moving endless cathode surface, means for flowing the electrolyte from one side of said cathode surn face to the other in a swift, continuous stream in contact with a portion of said cathode surface comprising conduit means of insoluble conductive material constituting an anode, means for stripping from said cathode surface the sheet material deosited thereon, and means for replenishlng the electrolyte with metal content after said electrolyte flows from in contact with said cathode surface.

15. Electrolytic apparatus for making sheet material comprising, in'combination, means providing a moving endless cathode surface, means comprising an insoluble conductive material constituting an anode the surface of which is in close proximity to said cathode surface for passing the electrolyte in a swift-flowing continuous stream transverse to the movement of said cathode surface, a body of soluble metal-bearing material, and means for Vflowing the electrolyte in contact with said metaLbearing ma-- terialafter the electrolyte leaves said cathode surface.

16. Electrolytic apparatus for makingsheet material comprising, in combination, means providing a moving endless cathode surface, means comprising an insoluble conductive material constituting an anode the Leonesa surface of which is in close proximity to said cathode surface for passing the electrolyte in a swift-flowing continuous stream from one side of said cathode surface to the other, a body of soluble metal bearing material, and means for liowing the electrolyte in contact with said metal bearing material fter the electrolyte leaves said cathode surace.

17. Electrolytic apparatus comprising, in combination, means providing a moving cathode surface, a body of soluble metalv 'a portion of said cathode surface, said means causing said electrolyte to flow over said portion of said cathode surface in a swift, continuous stream and comprising a con-` duit of insoluble conductive material constituting an anode in relatively close proximity to said cathodesurface.

19. Electrolytic apparatus comprising, in combination, means providing an endless moving'cathode surface, a body of soluble metal bearing material, means for circulating the electrolytein contact with said ma,

terial and said cathode surface, said means causing said electrolyte to flow over said cathode surface from one side thereof to the other in a swift, continuous stream and comprising a conduit of conductive material constituting an anode in relatively close proximity to said cathode surface. l

20. Electrolytic apparatus comprising, in combination, means providing an endless moving cathode surface, a body of soluble metal bearing material, means for circulating the electrolyte inv contact with said material and a portion of said cathode surface, said means causing said electrolyte to flow over said portion of said cathode surface from one side thereof to the other in a swift, continuous stream :and comprising avconduit of insoluble conductive material constituting an anode in relatively close proximity to said cathode surface.

21. Electrolytio apparatus for making sheet metal comprising, in combination, means forming an endless moving cathode surface, a trough in which said cathode surface moves, said trough Ibeing of insoluble conductive material constituting an anode the surface of which is distributed in relalyte with metal content comprising means for flowing the `electrolyte through said body in contact therewith after the electrolyte leaves said trough, and means for stripping from hsaid cathode surface the sheet of metal deposited thereon.

22. Electrolytic apparatus for making sheet metal comprising, in combination, means forming an' endless moving cathode surface, a trough in whichsaid cathode surface moves, said trough being of insoluble conductive material..constituting an anode the surface of which is distributed in relatively close proximity to said cathode surface, means for passing the electrolyte through said trough from one end 'thereofto the other between the surfaces of said cathode and anode in a swift-liowing continuous stream in contact with both surfaces, a body of soluble metal-bearing material, means for replenishing the electrolyte with metal content comprising means forflowing the electrolyte through said body in contact therewith after the electrolyte leaves said trough, and means for stripping from said cathode surface the sheet of metal deposited thereon.

23. Electrolytic apparatus for making sheet metal comprising, in combination, means forming a moving endless cathode surface, a trough in which said cathode surface moves, said trough being of insoluble conductive material constituting an anode the surfacenof which is distributed in relatively close proximity to said cathode surface, means for passing the electrolyte through said trough in a swift-tlowing continuous stream between said 'cathode' and anode surfaces, said cathode surface in the direction in which it moves being partially immersed in said stream, a body of soluble metal-bearing material, means for replenishing the electrolyte with metal content comy prising means for flowing the electrolyte` through said body in contact therewith after the electrolyte leaves said trough, and means for.A stripping from said cathode surface the sheet of metal deposited thereon.

24. Apparatus for depositing sheet metal comprising, in combination, a cathode'presenting a moving surface, conduit means for guiding an electrolyte in a swift-flowing continuous-stream past a portion of said cathode surface, said conduit means presenting` an electrically conductivetrough constituting an anode in relatively close proximity to the cathode surface.- v

25. Electrolytic apparatus for making sheet metal comprising, in combination,

means forming a moving endless cathode surface, a trough in which said cathode surface rotates, said trough having a surface of insoluble conductive material constituting an anode; means for circulating the electrolyte through said trough between and in contact with said cathode and anode surfaces, comprising means for causing the electrolyte to flow through said trough in a swift-flowing continuous stream; and means for stripping from said cathode surface the sheet of metaldeposited thereon. v

26. Electrolytic apparatusi for making sheet metal comprising, in combination, means forming a moving endless cathode surface, a trough in which said cathode surface rotates, said troughhaving a surface of insoluble conductive material constituting an anode; means for circulating the elec trolyte through said trough between and in contact with the cathode and anode surfaces, comprising means for causing the electrolyte to flow through said trough from one end thereof to the other in a swift-flowing continuous stream; and means for stripping from said cathode surface the sheet of metal deposited thereon. I

27. Electrolytic apparatus for making .sheet metal comprising, in combination, means forming a moving endless cathode surface, a trough in which said cathode surface moves, said trough having `a surface of insoluble conductive material constituting an anode, means for circulating the electro- .lyte causing it toflow through said trough in a swift-fiowng continuous stream in contact with the cathode and anode surfaces, means for replenishing the electrolyte with metal content after it leaves said trough and before it. again returns thereto, and means for stripping from said cathode surface the a swift-owing continuous stream between' v vand in contact with the cathode and anode surfaces, means for replenishing the electrolyte with metal content after it leaves said trough and before it again returns thereto, i

and means for stri ping from said cathode surface the sheet o metal deposited thereon.

29. Electrolytic apparatus comprising, in combination, a cathode, metal-bearing material for replenishing. the electrolyte, means for circulating the electrolyte to cause it to contact said cathode'and material in series, and means for 'varying the ratio of the amount ofelectrolyte to the amount of surface of said material on which said electrolyte acts.

30. Electrolytic apparat-us comprising, in combination, a cathode, a circulatory electrolytic bath carrying an impressed voltage, soluble anodic metal-bearing material in contact with the stream of electrolyte,4 the impressed voltage being such that the solution pressure of the metal of the metalbearing material exceeds the osmotic pressure or" the metal in solution, and means for maintaining the impressed voltage substan- -tially constant While varying the eieet thereof by changing the ratio of the amount of electrolyte to the amount of .surface of metal .bearing material on which the electrolyte acts.

3l. Electrolytic apparatus comprising, in combination, a cathode for deposition there on of metal from the electrolyte, means for replenishing the electrolyte With metal content coniprising circulating the electrolyte 'through metal-bearing material, and co-ntrolling means .or-eilecting an increase and decrease in the rate of replenishment.

32. Electrolytic apparatus comprising, in combination, a cathode for deposition therelon of metal from the electrolyte, meansV for -replenishingi the electrolyte with metal content comprisinfr circulating the electrolyte through metalnearing material, andineans for varying the'ratio of the amount of electrolyte to the amount of metal-bearing material through which the electrolyte flows.

33. Electrolytic apparatus comprising, in combination, a cathode on which metal is deposited, an electrolyte, a body 'of material for replenishing the metal content of the electrolyte, said electrolyte circulated in contact with said cathode and body of material in series, the' electrolyte and thebody of material both in excess' of the amount ,necessary to replace in the electrolyte the amount of metal deposited at the cathode, and means for varying the effective ratio between the electrolyte coming in contact With the body of material and the amount of material with which such electrolyte contacts thereby to preil'ent-.fvincrease and de- Acrease of the metallic content oi the electrolyte heyoiidthe desired limits.

An electrolytic method which coinprises depositing metal from a rapidly circiilated electrolyte, While replenishing themetallic content of the electrolyte alternately at a rate faster and slower than the `rate at which metal is deposited therefrom.

1 36. The method of electrolytically de positing metal, which comprises rapidly circulating in series the electrolyte past a cathode -and past a body of material for replenishing the metallic content of the 'electrolyte While alternately increasing and decreasing the metallic content of the electrolyte to maintain such content betWeen predetermined limits. y

87. The method of electrolytically depositing metal, which comprises continuously and rapidly circulating the electrotyle iii series past the cathode and through metal-bearing material for depositing metal on the cathode and for replenishing the electrolyte with metal in excess of that deposited on the cathode, and When a desired limit of the metallic content of the electrolyte'is ij reached decreasing suoli content.

3S. That method of electro-deposition, which comprises regulating the rate of replenishment of the metal content of an electrolytic cell during the. process of depositing in said cell.

39. The method of controlling the metalliccontent of an electrolyte which is continuously circulated past a cathode and an electrolyte replenishing metal, which comprises increasing and decreasing the ratio between the amount of electrolyte circulated past the replenishing metal and the aggregate surface of the latter.

10. Electrolytic apparatus comprising, in combination, means providing'a cathode surface, means providing a surface of conductive material constitutingl an anode distributed in relatively close proximity to .said cathode surface, soluble metal-bearing elect-rolyte replenishing material, means for rapidly circulating the electrolyte between the cathode and anode surfaces and through said metal-bearing materia-l, and meansfor lvarying the ratio of the. amountvofv electrolyte to the amount of surface of metalbearing material on which the electrolyte combinationq a cathode, metal-bearing mate! rial :ter replenishing the electrolyte, means for circulf` ting `the electrolyte to cause it to contact said cathode and material in series, and means. for varying the ratio 'of the amount of electrolyte to the amount of surface ot said material on which said electrolyte acts comprising a'regulatable 4ley-pass for diverting electrolyte around said material.

42. Electrolytic apparatus comprising, inv combination, aI cathode, metal-bearing mate- ,rial for rcplenishing the electrolyte, means ias for circulating the electrolyte to cause it to contact said cathode and-material in series,

a ley-pass for the electrolyte around said material, and means responsive to the s ecic gravity of the electrolyte for regulating monaco lating the electrolyte past said cathode and through said material, said means comprising a pump for elevating all the electrolyte assing said cathode to a level above said cathode and body of material, and a regulatable by-pass around said body of material for varying the amount of electrolyte passing through said material..

44. Electrolytic apparatus comprising, lin combination, a cathode, a body of soluble metal-bearing material for replenishing the electrolyte, means for continuously circulating the electrolyte past said cathode and through said material, said means comprising a pump for elevating all the electrolyte passing said cathode to a level above said cathode and body of material,` and regulatable means for varying theiratio of the amount of electrolyte to the amount of said material on which said electrolyte acts.

45. Electrolytic apparatus comprising, in combination, means providing a moving cathode surface, a trough, means causing the electrolyte to flow through said trough in a swift-flowing continuous stream, means causing said cathode surface 'to move through said trough with its surface distributed uniformly to the walls of said trough and entering and leaving said stream by way of the surface of said stream, and means for relatively adjusting the surface of said stream and said cathode surface to eifect substantially equal emersion of said cathode surface in said stream at all sections of said surface transverse to said stream.

46. Electrolytic apparatus comprising, in combination, means providing a moving endless cathode surface, a trough, means for causing the electrolyte to flow in a swift stream through said trough, means including a generally horizontal drum` for moving said cathode surface into and 'out of said stream, and means for maintaining the level of the electrolyte in said trough substantially parallel to the axis of said drum.

47. Electrolytic apparatus comprising, in

combination, means providing a moving end- 'Y less cathode surface, a trough, means for causing the electrolyte to dow in a swift stream through saidr trough, means including a generally horizontal drum for moving said cathode surface. into and out of said` stream, and means for maintaining the level of the electrolyte in said trough'substantially parallel to the axis of said drum comprising an undercut weir in said trough at the discharge side of said drum.

48. Electrolytic apparatus comprising, in combination, means providinga moving endless cathode surface, a trough', means for.

causing the electrolyte yto lowin a swift stream vthrough said trough, means including a drum for.. moving said cathode surface into and out of said stream, and means kfor maintaining the level of .the electrolyte in saidtrough substantially parallel to the axis i of said drum comprising 'flow Acontrolling lmeansin said trough atthe dischargeside o said drum.

49. Electrolytic apparatus comprising, inl

combination, lmeans providing'a .moving endless cathode surface, a trough, means forkcausing the 'electrolyte to lpw in ya swift stream throu h said trough, means including a generaly'horizontal drum .for moving said cathode surface into and out of said stream, and means for maintaining the level of the electrolyte in said 'trough substantially parallel to the axis of said drum comprismg means in said trough at `the discharge side of said'drum for restricting the flow of electrolyte at the surface level thereof.

50. Electrolytic apparatus comprising, vin combination, a trough, a drum rotating in said trough, said drum having a cylindrical portion provided with a .cathode surface and having tapered ends, the .axis of saiddrum being lengthwise of said trou h,l andlmeans for causingthe electrolyte to ow in aswift v continuous stream through said trough.

51..-Ele'ctrolytic apparatus comprising, in combination, a plurality ofielectrolytic units `each comprising acathode for deposition thereon of metal from the electrolyte, means for replacing in the electrolyte the metal deposited therefrom on the cathodes l.of said units comprising a common lbody `of metalbearing material through which electrolyte from all of said units is assed, and means for controlling the rate o such replacement of metal.

52,Electrolytic apparatus comprising, in combination, a plurality of means eachy rovidedI with a moving cathode .sur ace, troughs of insoluble .conductive material constituting anodes in which said cathode surfaces move, means for passing the electrolyte in a swift-flowing stream ythrough said troughs in contact with said cathodes, abody of soluble metal-bearing material,

means for circulating the electrolyte through saidV plurality of troughs and body of material, and means for controlling the rate of solutionl of metal into the electrolyte from said body of metal-bearing material.

53. Electrolytic apparatus comprising, in combination, a plurality of means each provided With movlng cathode surfaces, troughs of insoluble conductive material constituting anodes in which said cathode surfaces move, means for passing the electrolyte in a swift-flowing stream through said troughs in contact with said cathodes, a body of soluble metal-bearing material, means for circulating the electrolyte through said plurality of troughs and body of material, and means for varying the ratio of the amount of electrolyte to the amount of said material on which said electrolyte "acts. D l 54. Electrolytic apparatus comprising, in combination, a plurality of means each provided with moving cathode sui-faces, troughs of insoluble conductive material constituting anodes in which said cathode surfaces move` a body of soluble metal-bearing material, means for circulating the electrolyte through said plurality of troughs in a swift-iiowing stream in contact with said cathodes and through said body of material, and a by-pass for diverting a portion of the electrolyte around said bodyof material.

55. Electrolytic apparatus comprising, in combination, a plurality of electrolytic units each comprising a cathode and an anode of insoluble conductive material, a tower containing soluble metal-bearing material, means for circulating the electrolyte through said units and tower comprising a pump for elevating the electrolyte and causing it to ow through said tower and hence to said units by gravity. n

56. Electrolytic apparatus comprising, in combination, a plurality of elcctrolytic units each comprising a cathode and an anode of insoluble conductive material, a tower containing soluble metal-bearing material, means for circulating the electrolyte through said units and tower comprising a pump for elevating the electrolyte and causing it to flow through said tower and hence to said units by gravity, and means for varying the ratio of the amount of electrolyte to the amount of said material on which said electrolyte acts.`

57. Electrolytic apparatus comprising, in combination, a plurality of electrolytic units each comprising a cathode and an anode of insoluble conductive material, a tower containing soluble metal-bearing lmaterial, means for circulating the electrolyte through said units and tower comprising a pump for elevating the electrolyte and causing it to flow through said tower and hence to said units by gravity, and a by-pass for diverting a portion of the electrolyte around said soluble material.

58. Electrolytic apparatus comprising, in combination, a trough through which the electrolyte flows, an endless conductor moving in said trough, a body of soluble metalbearing material for replenishing the electrolyte, a chamber into which the electrolyte discharges from said troughby gravity, and a pump and conduit means for elevating the electrolyte from said chamber for effecting flow of electrolyte through said trough and body ofsoluble metal-bearing material.

59. That method of making metallic prises rotating a cathode in close proximity to an anode of insoluble conductive material circulating the electrolyte to cause it to pass in a continuous swift-flowing stream between the anode and cathode, and replenish ing the electrolyte with metal content after it passes from between the cathode and anode.

60. The method of making metallic sheets which comprises moving a cathode in close proximity to an anode of insoluble conductive material, circulating the electrolyte to cause it to pass between said cathode and anode in a swift-fiowing continuous stream and then to pass through soluble metal-bearing materia 61. The method of making metallic sheets which comprises moving a cathode in close proximity to an anode of insoluble conductive material, circulating the electrolyte to cause it to pass between said cathode and anode in a swift-flowin continuous stream, while part of the catho e is in contact therewith, and while passing the electrolyte in contact with soluble metal bearing ma terial.'

62. The method of making metallic sheets by electro-deposition which comprises moving a cathode in close proximity to .an anode of insoluble conductive material, circulating the electrolyte to cause it to pass in a continuous swift-flowing stream between the anode and cathode, while part of the cathode is in contact therewith, and replenishing the metal content of the electrolyte after it passes 'from between the cathode and anode.

63. The method of electro-depositing copper which comprises circulating the electrolyte to cause it to flow between the surface of a cathode and the surface of insoluble conductive material in a swift continuous stream and to flow in contact with copperbearing material on which is impressed a voltage of not less than one and one-half v66; Electrolytic apparatus for making metal4 sheets, comprising, in combination,

means providing a rotating cylindrical cathode surface abutting at its ends with a ring ofrubber, and means for stripping from the "cathode surface the sheet deposited thereon. sheets by electro-deposition which `comcontent of an electrolyte which comprises allowing the electrolyte to act on metal-bear- 10 ing material While controlling the rate of solution of metal by varying the amount of the electrolyte acting on said material.

In testimony whereof, Il have signed my name to this s ecification. M TTHEW M. MERRITT. 

